Metal–organic framework aerogels (MOAs) embedded with CdS (CdS/MOA(Cr)) synthesized via a facile one-pot solvothermal method have a larger surface area than pristine MOA(Cr) and the post-synthesized composite. CdS/MOA(Cr) exhibited 5 times enhancement in the photocatalytic activity than that of pure CdS for Cr(VI) reduction under visible light without adding any sacrificial agent, due to the larger surface area and photosensitazation of MOA(Cr).